Electrical connectors

ABSTRACT

942,511. Two-part couplings. BURNDY CORPORATION. Oct. 2, 1961 [Oct. 6, 1960], No. 35468/61. Heading H2E. A socket contact 2 comprises a contact pin receiving bore 4 constricted to the pin diameter by two annular beads such as 20, and including a portion 24 formed like a leaf spring by transverse and longitudinal sawcuts in the socket wall. The portions 24 may be given a permanent set towards the centre of the bore. An embodiment (Fig. 3, not shown) incorporates three beads with the central bead formed on the free ends of the leaf spring and of an initial diameter less than that of the contact pin.

April 14, 1964 P. DUPRE ETAL ELECTRICAL CONNECTORS Filed Oct. 6, 1960 HENRY P. DUFRE GLENN M. OSBORN ATTORN United States Patent 3,129,050 ELECTRICAL CUNNECTORS Henry I. Dupre, Wilton, and Glenn M. Osborn, Old Greenwich, Conn., assignors to Burndy Corporation, a corporation of New York Filed Oct. 6, 196i), Ser. No. 61,006 2 Ciaims. (Cl. 339-458) This invention relates toelectrical connectors, and more particularly, to socket contacts for pin and socket type connectors.

Pin and socket type connectors are well known in the prior art, andare to be foundiin various :shapes and configurations. The rudimentary connector `consists of a smooth, uniform diameter pin which is inserted into a mating, smooth, uniform diameter socket. Good electrical contact therebetween is dependent on a tight frictional fit between the pin and socket. Since close manufacturing tolerances are difiicult to obtain, it has become cus-4 tomary to make either the pin or the socket of resilient construction. While suchy an arrangement is practical, there is generally no definite, specific and invariable point of good electrical contact between the contacts. Rather there is a large intersurface area in which, depending on the exact surface configuration produced by the vagaries of manufacture, electrical contact might somewhere be made. This results in a variable and often high contact resistance between the pin andthe socket.

A common resilient socket variant is a tubular socket having an unbroken periphery at its pin receiving end, and a leaf spring formed out of 'a part of said socket wall by means of a transverse and then longitudinal saw cut. The leaf is then set so that it depends towards the center of the socket. When the pin is inserted into the socket it biases the leaf outwardly and is pressed thereby against the wall of the socket opposite the leaf.

Another common resilient socket variant is a tubular socket which is slit longitudinally at its pin receiving end to provide a plurality of resilient fingers. The fingers are biasedv towards the center of the socket. When the pin is inserted into the socket it biases the fingers outwardly, the lingers thereby gripping the pin.

The leaf spring socket has a major advantage over the split finger socket. An oversize pin or probe may be inserted into a split finger socket, spreading apart and permanently distorting the lingers. The leaf spring socket has an unbroken periphery at its end which naturally prevents the entry of a grossly overdiameter pin, and thereby prevents permanent distortion of its leaf spring. This feature is commonly known as closed-entry. A recent improvement to the split finger socket has been to provide an end cap or closed entry adapter which fits over the ends of the split fingers and has a central bore with an unbroken periphery. This adapter both limits the diameter of the pin which may be inserted therethrough, and the spreading out of the ends of the split fingers.

To establish a definite and invariable contact area between the pin and the socket, an improvement has become known in the split finger type socket of providing a roll or bead on the inner wall of the ends of the split fingers. The pin always makes contact with the lingers at this bead. By controlling the resiliency of the fingers and thus the force applied to the pin, and the width of the bead, a substantially uniform and fixed contact area and resistance can be obtained. Since the contact area is provided by the relatively small area of the bead, rather than the total area of the socket, for a given force relatively high contact pressure can be obtained. These high contact pressures are useful in breaking down any coatings which might develop on the surface of the pin, and in providing a low contact resistance. This bead, however, raises a disadvantage. The pin effectively contacts the ICC socket at the bead, and since the rest of the socket is of larger diameter than the bead, the pin has a tendency to wiggle in the socket.

If the above described Contact bead of the split Vfinger socket is directly incorporated into the leafspring socket to obtain the advantage of a fixed contact area high pressure and low resistance, a disadvantage results. The inner diameter of the bead must be substantially that of the pin. Therefore, the inner diameter of the rest of 'the socket must be significantly greater vthan the pin. An obvious expedient wouldy be to provide a separate closed entry adapter over the end of the socket to reduce the entrance diameter of the socket bore. This requires a separate part and anadditional assembly operation. Another expedient would be to flange inwardly the end of the socket. This requires an independent manufacturing operation and often produces Aa burr which would scrape the surface of the vpin as it is inserted.

It should be noted that the sawing operation-in both the leaf spring and the split linger sockets produces a burr. This burr in the prior art devices interfered with the inserted pin and had to be removed.

It is, therefore, an object of this invention to lprovide a leafy spring socket having a contact bead, .and an integral closed entry feature.

Another object is to provide the abovementioned socket with its contact bead and integral closed entry feature in substantially the same manufacturing operation.

Still another object is to provide the kabovementioned socket with an integralclosed entry feature which has no burr which will interfere with an inserted pin.

Yet another object is to provide the abovementioned socket with an independent pin cleaningl pressure means, and anindependent pin contacting pressure means.

A feature-of thisinvention Vis a leaf spring socket having a first internall annular bead on the end ofI its springv and adjacent socket and a second annular bead between the end of the socket and the end of the leaf spring.

These and other objects and features of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a top view of a spring leaf socket embodying this invention;

FIG. 2 is a front View in cross-section of the socket of FIG. l;

FIG. 3 is a top view of second embodiment of this invention; and

FIG. 4 is a front view in cross-section of the embodiment of FIG. 3.

Referring to FIGS. l and 2, a spring leaf socket type contact 2 is shown having a pin receiving socket 4 and a conductor receiving socket 6. The conductor receiving socket may include a peepehole 8, a conductor socket 10 and an insulation shroud 12. The conductor (not shown) may be secured to the socket by any suitable means, e.g. crimping or soldering.

The pin receiving socket 4 has a bore 14 and may have a necked portion 16 adapted to receive a locking spring (not shown) to cooperate with contact shoulder 18 in locking the contact into its housing (not shown). A first annular bead 20 is rolled into the socket periphery to provide a fixed and relatively small pin-contacting area. The inner diameter of this bead is substantially equal to the diameter of the contact pin 21 (shown in dot-dash lines in FIGURE 2) which the socket is to receive. A second annular bead 22 is rolled into the socket periphery adjacent the end of the socket. The inner diameter of this bead is also substantially equal to the diameter of the Contact pin; and provides the closed entry feature and, if desired, a second relatively small pin-contacting area. A pin or probe greater than the inner diameter of the second bead can not be forced beyond this unbroken peripherial bead into the socket.

The spring leaf 24 of the socket is formed by transverse 26 and longitudinal 28 saw cuts into the medial portion of the socket. The free end 30 of the leaf may be given a permanent set towards the center of the bore.

The two rolls provide smooth, burr free surfaces to contact the inserted contact pin Without damage thereto. A burr caused by the sawing of the spring leaf or cutting the end of the socket will be spaced away from the contact pin. If it is desired, these burrs may be removed by a suitable electro-chemical treamtent.

It will be seen that the second bead 22 besides providing the closed entry feature, rnay be formed to a diameter equal to that of the inserted pin. The roll will then apply a high pressure to the pin as it is inserted, cleaning the surface of the pin as it passes thereunder. The first bead 20 will provide a high pressure, small area contact to the pin, ensuring a uniform, low resistance contact therewith.

A second embodiment of the invention is shown in FIGS. 3 and 4. The leaf spring socket contact 102 has a iirst annular bead 120 having an inner diameter less than the diameter of the contact pin 121 (shown in dot dash lines in FIGURE 4) to be inserted. A second annular bead 122 having an inner diameter substantially equal to the contact pin is formed at the socket end to provide the closed entry feature. A third annular bead 123 having an inner diameter substantially equal to the contact pin is formed in the socket proximal the xed end of the leaf. The leaf 124 is cut out of the socket wall and set towards the bore. This provides a three point longitudinal contact between the portion of the rst bead on the free end of the leaf, and the opposed areas of the second andy third beads, avoiding any wiggle of the pin in the socket.

The invention has thus been described, but it is desired to be understood that it is not confined to the particular forms or usages shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of the invention, and, therefore, the right is broadly claimed to employ all equivalent instrumentalities coming within the scope of the appendent claims, and by means of which objects of this invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to obtain these objects and accomplish these results.

We claim:

1. A connector comprising a socket contact and a mating pin contact having a given diameter; said socket having a bore of diameter greater than said given diameter including an open end adapted to receive said pin contact; said bore including an unbroken annulus located substantially at the bore open end, and a longitudinally disposed leaf spring formed into and from a portion of the wall of said socket and depending into substantially the medial length of said bore; a rst internal annular bead formed in a section of said bore including said unbroken annulus; a second internal annular bead formed in a section of said bore including said leaf spring; the inner diameter of said rst and second beads being substantially equal to the diameter of said pin Contact. u"ZJ connector according to clairrrl further including a third annular bead in said bore longitudinally spaced from said second bead on the side thereof remote from said first bead.

References Cited in the tile of this patent UNITED STATES PATENTS 2,004,550 Bradley June 11, 1935 2,346,831 Drury Apr. 18, 1944 2,443,513 Quackenbush June l5, 1948 2,455,324 Wagstaff Nov. 30, 1948 2,677,116 Ritter Apr. 27, 1954 2,781,498 Maly Feb. 12, 1957 2,942,231 Cornell June 21, 1960 2,992,403 Hawk July 11, 1961 FOREIGN PATENTS Australia Jan. 14, 1926 of 1926 69,426 France July 15, 1958 (First addition to No. 1,137,079) 1,184,311 France Feb. 2, 1959 433,622 Great Britain Aug. 19, 1935 561,037 Great Britain May 2, 1944 

1. A CONNECTOR COMPRISING A SOCKET CONTACT AND A MATING PIN CONTACT HAVING A GIVEN DIAMETER; SAID SOCKET HAVING A BORE OF DIAMETER GREATER THAN SAID GIVEN DIAMETER INCLUDING AN OPEN END ADAPTED TO RECEIVE SAID PIN CONTACT; SAID BORE INCLUDING AN UNBROKEN ANNULUS LOCATED SUBSTANTIALLY AT THE BORE OPEN END, AND A LONGITUDINALLY DISPOSED LEAF SPRING FORMED INTO AND FROM A PORTION OF THE WALL OF SAID SOCKET AND DEPENDING INTO SUBSTANTIALLY THE MEDIAL LENGTH OF SAID BORE; A FIRST INTERNAL ANNULAR BEAD FORMED IN A SECTION OF SAID BORE INCLUDING SAID UNBROKEN ANNULUS; A SECOND INTERNAL ANNULAR BEAD FORMED IN A SECTION OF SAID BORE INCLUDING SAID LEAF SPRING; THE INNER DIAMETER OF SAID FIRST AND SECOND BEADS BEING SUBSTANTIALLY EQUAL TO THE DIAMETER OF SAID PIN CONTACT. 